The present invention generally relates to a mechanism that generates a force in a hand-held user input device used in connection with a host computing device, and more specifically, to a mechanism that imparts a directional haptic feedback on the housing of a hand-held user input device in response to a signal from a host computing device.
A number of haptic user input devices have been developed to provide force feedback in response to a signal from a host computer, e.g., during simulations or game play executed on the host computer. For example, Microsoft Corporation""s SIDEWINDER(trademark) joystick provides haptic feedback to a user gripping the joystick in response to events occurring in computer games, based upon commands transmitted from a host computer to the joystick. For instance, if a simulated character displayed during execution of a computer game is struck by a simulated projectile, such as a boulder, a signal from the host computer causes an actuator in the joystick housing to abruptly move the joystick in the same direction as the path of the simulated projectile. The force produced by the actuator on the control handle imparts a haptic sensation to the user""s hand, which is gripping the joystick control handle, indicating that the character has been hit by the projectile. In another instance, if a user commands a simulated character to move into a simulated wall, by moving the joystick control handle in an appropriate direction, a signal from the host computer causes the actuator to produce a force that resists the user""s movement of the joystick control hand in that direction. This force imparts a haptic sensation to the user""s hand that is gripping the joystick to indicate that the simulated character controlled by the joystick has run into the wall.
Similarly, Microsoft Corporation""s SIDEWINDER(trademark) wheel provides haptic feedback to a user gripping the wheel and using it to control a simulated vehicle, in response to a signal from the host computer on which the vehicle simulation is executed. If a simulated vehicle strikes and rebounds from a simulated wall, a signal from the simulation causes an actuator coupled to a shaft on which the wheel is mounted to abruptly turn the wheel in the same direction as the simulated vehicle is rebounding. The wheel also vibrates in response to a simulated rough surface over which the vehicle is traveling.
In contrast to haptic joysticks and haptic wheels, force feedback is typically applied to gamepad input devices in a different manner. A gamepad input device uses a multi-position rocker switch that is normally actuated by a user""s thumb to provide input signals that control objects on a screen of a host computer or computing device. Since a gamepad input device does not include a control handle or wheel that is gripped by a user, haptic feedback cannot be applied directly to a control component that is held by the user. Instead, in prior art haptic gamepad input devices, a vibration that is applied to the housing of the gamepad has been produced in response to a signal from the host computing device. Vibration of the housing of a gamepad user input device is often produced by rotating offset counter weights or by energizing and de-energizing an electromagnetic device to vibrate a ferromagnetic mass. Such vibration does not provide a directional force feedback along a specific axis. Directionless vibration is thus currently used for several gamepad hand-held devices that do not include a joystick control handle, a wheel, or other control member that can be gripped and moved relative to the housing of the device. The relatively simple mechanisms that provide vibration do not add substantial weight to a gamepad, making it more comfortable for the user to support.
However, it would be desirable to enhance a user""s experience with a handheld input device such as a gamepad by providing directional haptic feedback to the user. One approach was disclosed in commonly assigned U.S. Pat. No. 5,643,087, which describes a hand-held input device with a moveable member that cradles a thumb or other digit of the user""s hand. The moveable member is thus comparable to a non-graspable mini joystick control handle, but provides more effective contact with the user by at least partially looping around the user""s digit. The moveable member can be moved relative to two orthogonal axes and receives a haptic force directed along one or both of these orthogonal axes.
While the above approach is effective, the directional haptic feedback is primarily limited to a single digit of a user. It would therefore be desirable to provide directional haptic feedback to at least one of the user""s hands, as is currently provided by grasping the control handle or wheel of haptic devices, but without requiring a large graspable control member on the input device.
In accord with the present invention, an input device is defined that provides a directed force feedback sensation to a user holding the device. The input device comprises a housing that is adapted to be handheld, i.e., sufficiently small to be supported in an operator""s hand. A prime mover is disposed within the housing and is operatively coupled to a mass. The prime mover causes the mass to move in response to a control signal received from a host device. A directional force is imparted to the housing when the mass starts and stops moving due to a change in momentum of the mass, providing a haptic sensation that is directed through the housing to the user holding the housing.
Preferably, the primer mover comprises an electric motor that rotates a motor shaft to move the mass. The input device can also include a sensor for determining a position, velocity and/or acceleration of the mass, directly, or indirectly, such as by monitoring a rotation angle of the shaft.
The input device preferably employs a transmission to couple the prime mover to the mass, causing the mass to move. Also preferably, the transmission is a gear drive in which a first gear on an end of the shaft is coupled to a second gear. The second gear is pivotally mounted to the housing. Connected to the second gear is an arm that extends outwardly, normal to an axis of rotation of the second gear. The mass is attached at a distal end of the arm, so that as the first gear drives the second gear in rotation about a pivot point, the mass moves through an arc.
The mass is thus driven through at least a portion of the arc, and when stopped abruptly, imparts a reactive force to the housing in a linear direction generally tangent to the arc of the mass. The direction of this reactive force can be selectively modified by changing the disposition of the arc and a stopping point of the mass along the arc. Alternatively, or in addition, the mass is stopped when the mass or arm contacts a mechanical stop.
In another embodiment, the mass is moved through an arc by a mechanically linked arm. A transmission for this embodiment includes a threaded shaft that is rotated by the actuator. The actuator either drives the shaft directly, or alternatively, through a pair of bevel gears. The threads of the shaft mesh with internal threads of a lead nut that moves along at least a portion of the length of the shaft as the shaft rotates. The nut has a pin extending normal to the axis of the shaft and into a slot disposed in a proximal end of the linkage arm. As the nut moves along the length of the shaft, the pin acts against an edge of the slot in the arm, causing the arm to pivot about a pivot point. A distal end of the arm, to which the mass is attached, pivots about the pivot point in the same rotational direction as the proximal end of the arm. When the nut stops, the pin contacts the opposite edge of the slot in the arm, causing the arm and mass to stop at a point along the arc. Alternatively, or in addition, the mass may stop when the mass, linkage arm, or nut contacts a mechanical stop.
Yet another embodiment simply uses a nut as the mass. The nut is prevented from rotating with the shaft and instead, moves along the shaft as the threaded shaft rotates. The mass stops at end points or when the shaft stops.
The present invention preferably further comprises a controller that energizes the prime mover, causing the prime mover to move the mass in response to the control signal received from a host device, such as a computer, set top box, video game controller, electronic game, or toy to which the input device is coupled. In addition, the force signal may be in response to a schedule of commands stored in a memory included in the input device.
Another aspect of the invention is a method for developing a directional haptic force on a housing of an input device. The method includes steps that are generally consistent with the functions implemented by the components of the apparatus described above.